A short, self-administered questionnaire, the Dissociative Experience Scale (DES), has been developed and tested. The DES reliably and validly measures frequency and types of dissociative phenomena. This instrument has been administered to a wide variety of carefully diagnosed psychiatric groups. The DES has been included in over 50 studies in the United States and abroad and has been translated into French, Dutch and Cambodian. Current research using this instrument includes studies of patients with epilepsy, eating disorders, borderline personality disorder, affective disorders and schizophrenia in conjunction with researchers in the IRP, NIMH; NINCDS; and the Department of Psychiatry, UCLA and the Department of Psychology, The American University.